Fusion-iO just announced the new ioDrive2 and ioDrive2 Duo on Oct 2011 (at some conference of no importance).
The MLC models will be available late November and the SLC models afterwards.
See the Fusion-iO
press release for more info.
Below are the Fusion-IO ioDrive2 and ioDrive2 Duo specifications.
The general idea seems to be for the ioDrive2 to match the realizable bandwidth of a PCI-E gen2 x4 slot (1.6GB/s)
and for the ioDrive2 Duo to match the bandwidth of a PCI-E gen2 x8 slot (3.2GB/s).
I assume that there is a good explanation why most models have specifications slightly below the corresponding PCI-E limits.
The exception is that 365GB model at about 50% of the PCI-E g2 x4 limit.
Suppose that the 785GB model implement parallelism with 16 channels and 4 die per channel.
Rather than building the 365GB model with the same 16 channels,
but a different NAND package with 2 die each, they just implemented 8 channels using the same 4 die per package.
Lets see if Fusion explains this detail.
Fusion-IO ioDrive2
| ioDrive2 Capacity | 400GB | 600GB | 365GB | 785GB | 1.2TB |
|---|
| NAND Type |
SLC (Single Level Cell) |
MLC (Multi Level Cell) |
| Read Bandwidth (64kB) |
1.4 GB/s |
1.5 GB/s |
710 MB/s |
1.2 GB/s |
1.3 GB/s |
| Write Bandwidth (64kB) |
1.3 GB/s |
1.3 GB/s |
560 MB/s |
1.0 GB/s |
1.2 GB/s |
| Read IOPS (512 Byte) |
351,000 |
352,000 |
84,000 |
87,000 |
92,000 |
| Write IOPS (512 Byte) |
511,000 |
514,000 |
502,000 |
509,000 |
512,000 |
| Read Access Latency |
47 µs |
47 µs |
68 µs |
68 µs |
68 µs |
| Write Access Latency |
15 µs |
15 µs |
15 µs |
15 µs |
15 µs |
| Bus Interface |
PCI-E Gen 2 x4 |
| Price |
$? |
? |
$5,950? |
$? |
? |
Fusion-IO ioDrive2 Duo
| ioDrive2 Capacity | 1.2TB | 2.4TB |
|---|
| NAND Type |
SLC (Single Level Cell) |
MLC (Multi Level Cell) |
| Read Bandwidth (64kB) |
3.0 GB/s |
2.6 GB/s |
| Write Bandwidth (64kB) |
2.6 GB/s |
2.4 GB/s |
| Read IOPS (512 Byte) |
702,000 |
179,000 |
| Write IOPS (512 Byte) |
937,000 |
922,000 |
| Read Access Latency |
47 µs |
68 µs |
| Write Access Latency |
15 µs |
15 µs |
| Bus Interface |
PCI-E Gen 2 x8 |
| Price |
$? |
? |
SLC verus MLC NAND
Between the SLC and MLC models, the SLC models have much better 512-byte reads IOPS than the MLC models,
with only moderately better bandwidth and read latency.
Not mentioned, but common knowledge is that SLC NAND has much greater write-cycle endure than MLC NAND.
It is my opinion that most database, transaction processing and DW, can accommodate MLC NAND
characteristics and limitations in return for the lower cost per TB.
I would consider budgeting a replacement set of SSDs if analysis shows that the MLC life-cycle does not match
the expected system life-cycle.
Of course, I am also an advocate of replacing the main production database server on a 2-3 year cycle
instead of the traditional (bean-counter) 5-year practice.
The difference in read IOPS at 512B is probably not important. If the ioDrive2 MLC models can drive 70K+ read IOPS at 8KB, then it does not matter what the 512B IOPS is.
Post-RAID?
One point from the press release:
"new intelligent self-healing feature called Adaptive FlashBack provides complete chip level fault tolerance,
which enables ioMemory to repair itself after a single chip or a multi chip failure without interrupting business continuity."
For DW systems, I would like to completely do away with RAID when using SSDs,
instead having two system without RAID on SSD units.
By this, I mean fault-tolerance should be pushed into the SSD at the unit level. Depending the failure rate of the controller, perhaps there could be two controllers on each SSD unit.
For a critical transaction processing system, it would be nice if Fusion could provide failure statistics
for units that have been in production for more than 30 days
(or whatever the infant mortality period is) on the assumption that most environments will spend a certain amount
of time to spin up a new production system.
If the failure rate for a system with 2-10 SSDs is less than 1 per year,
then perhaps even a transaction processing system using mirroring for high-availability can also do
without RAID on the SSD?
ioDrive2 and ioDrive2 Duo
I do think that it is great idea for Fusion to offer both the ioDrive2 and ioDrive2 Duo product lines
matched to PCI-E gen2 x4 and x8 bandwidths respectively.
The reason is that server systems typically have a mix of PCI-E x4 and x8 slots
with no clear explanation of the reasoning for the exact mix,
other than perhaps that being demanded by the customer complaining the loudest.
By have both the ioDrive2 and Duo, it is possible to fully utilize the bandwidth from all available slots
balanced correctly.
It would have been an even better idea if the Duo is actually a daughter card the plugs onto the
ioDrive2 base unit, so the base model can be converted to a Duo,
but Fusion apparently neglected to solicit my advice on this matter.
I am also inclined to think that there should also be an ioDrive2 Duo MLC model
at 1.2TB, on the assumption that the performance will be similar to the 2.4TB model,
as the ioDrive2 765GB and 1.2TB models have similar performance specifications.
The reason is that a database server should be configuration with serious brute force IO capability,
that is, all open PCI-E gen 2 slots should be populated.
But not every system will need the x8 slots populated with the 2.4TB MLC model,
hence the viability of a 1.2TB model as well.
ps
if Fusion should be interested in precise quantitative analysis for SQL Server performance, instead of the rubish whitepapers put out by typical system vendors,
well I can turn a good performance report very quickly. Of course I would need to keep the cards a while for continuing analysis...